The first line of the input contains a single integer $T$ ($1 \le T \le 100$), the number of test cases.
The first line of each test case contains a single integer $n$ ($1 \le n \le 10^5$), the length of each of the strings.
Each of the following two-line contains a string of $n$ lowercase English letters, representing string $s$ and $t$, respectively.
It is guaranteed that it is possible to make string $s$ equal to string $t$ using zero or more Split and Swap
operations.
The total sum of $n$ over all test cases doesn't exceed $2 \times 10^6$.